The present invention generally relates to a lancet system, and more particularly relates to a lancet system comprising at least one lancet having a lancet tip protected by a sterile protector.
The removal of body fluids such as blood is performed with the aim of subsequent analysis to diagnose illnesses or monitor the state of a patient's metabolism. Diabetics, in particular, remove samples of blood to determine the concentration of blood sugar. In order to remove only small amounts of blood, sharp, sterile lancets are quickly pierced into a patient's fingertip or other body part, for example, by hospital staff or by the patient himself. Lancet systems and other similar devices (for example, blood taking equipment, blood lancet devices, or pricking aids) which extract blood with minimal pain and in a reproducible manner are provided especially in the area of “home-monitoring,” in which lay people carry out simple analyses of their blood.
Lancet tips used for blood extraction are typically sterilized in advance and are stored in a sterile state via a sterile protector (for example, in the form of a cap or pocket) before the lancet is used for a puncturing operation to prevent the tip from being contaminated by the surroundings. Furthermore, measures are frequently taken to ensure that, after a puncturing operation has taken place, the lancet tip is shielded or protected again (for example, by the same cap or pocket) to prevent injury and infections from blood that remains adhered to the lancet tip.
In the case of individual lancets, a sterile protector can be produced, for example, by encapsulating the lancet tip with plastic by injection molding both the lancet body and sterile protector during the same process. Before the lancet is used, the user manually removes the sterile protector upon inserting the lancet body into a pricking aid. In the case of lancets being encased in a magazine, similar sterile protectors are customary in which the lancet is pulled out of the sterile protector, whereby the sterile protector is moved out of the puncture path by a spring force. Relatively complicated mechanisms, such as springs, are integrated into the equipment to carry out this function.
Document WO 01/66010 discloses a lancet system that circumvents the complicated nature of this mechanism by piercing the sterile protector. In particular, document WO 01/66010 relates to a lancet comprising a lancet needle with a tip and a lancet body which completely surrounds the lancet needle at least in the region of the tip. In the region around the tip, the lancet body is composed of an elastic material in which the tip of the lancet needle is embedded. Furthermore, a lancet is disclosed having a lancet needle with a tip and a hollow body which surrounds at least the tip of the lancet needle. The lancet needle is movable in the region of its tip inside the hollow body or housing, and the hollow body or housing is at least partially composed of an elastic material which can be punctured by the tip of the lancet needle during the puncturing operation. Further, and if appropriate, the hollow body or housing closes again after the tip of the lancet needle completes a puncturing operation and is retracted into the hollow body or housing.
Document DE 28 03 345 relates to equipment used for collecting blood samples that have a needle which can be applied to a patient's body part and an actuating device which has a ram and trigger for applying force to the needle in the direction of the needle tip. Blood lancets are used as needles and are individually disposed inside pockets of a strip package and are introduced into the equipment by a transporting device which acts on the strip package. The blood lancets are removed from the equipment after use, but while disposed inside the pockets, the ram of the actuating device drives the blood lancets. This equipment can either contain a cutting device by which the portion or region of the strip package closest to the needle tip can be severed before the application of force, or the blood lancets can perforate the strip package under the application of force.
U.S. Publication No. 2003/0199893 discloses a cutting device for cutting open a sterile barrier, but this requires substantial mechanical effort. The sterile barrier surrounds a penetrating element before a puncture operation and the barrier can either be opened by the cutting device or the penetrating element itself can penetrate through the sterile barrier.
In general, lancet systems should not be reused after having already performed a puncture operation. However, in home-monitoring environments, it is conceivable that a lancet system, once inserted into a pricking aid, will be used repeatedly by the same user before it is thrown away and replaced by a new lancet system. In a lancet system in which the sterile protector is pierced by the lancet itself to open the protector during a first puncture operation, after the first puncture operation, at least a portion of the sterile protector passes again in front of the lancet tip as the tip is retracted into the sterile protector. If a previously used lancet is reused, there is a risk that the used lancet will not pass through the originally created opening in the sterile protector, but rather will pierce a new opening in the sterile protector. In general, the lancet tip is not designed for piercing multiple openings, but rather for pricking skin with minimal pain. Upon each subsequent piercing of the sterile protector, which can be in the form of, for example, plastic material, the sharpness of the lancet tip begins to deteriorate. Further, after multiple puncture operations, parts of the sterile protector may detach from the sterile protector and possibly enter the pricking wound together with the lancet tip, which must be avoided.
Additionally, lancet systems known in the prior art are disadvantageous in that, during the retraction of the lancet tip through the outlet opening and into its original sterile protector, blood residues adhering to the lancet tip can scrape off at the edge of the outlet opening and adhere or attach to the outside of the sterile protector, thereby undesirably contaminating the surroundings.